Insulin Resistance in Healthy U.S. Adults: Findings from the National Health and Nutrition Examination Survey (NHANES)

Abstract

Background: Insulin is fundamental in two conditions that are epidemic in the United States and globally: obesity and type II diabetes. Given insulin's established mechanistic involvement in energy balance and glucose tolerance, we examined its relationship to common health-related endpoints in a large population-based sample. Methods: The National Health and Nutrition Examination Survey is a cross-sectional study that uses a complex multistage probability design to obtain a representative sample of the United States population. Adult participants were included from 8 successive 2-year data waves (1999–2014), including 9,224 normal individuals, 7,699 prediabetic, and 3,413 diabetic subjects. The homeostatic model for insulin resistance (HOMA-IR) was available for 20,336 participants and its relationship with demographic, anthropometric, and clinical data was analyzed. We examined the relationship of HOMA-IR to 8 groups of outcome variables: general health, anthropometric/metabolic [waist size, body mass index (BMI)], cardiovascular (blood pressure), lipid [triglycerides, high-density lipoprotein (HDL)], hepatic [alanine aminotransferase (ALT), gamma-glutamyl transferase (GGT)], hematologic [white blood cells (WBC), hemoglobin (Hgb), platelets], inflammatory (C-reactive protein), and nutritional (vitamins D and C, serum folate, and pyridoxine) variables. Results: HOMA-IR was generally strongly, monotonically, and highly significantly associated with adjusted outcomes in normal subjects, although clinical laboratory values were generally within normal bounds across insulin quartiles. In the normal subset, the odds ratio and 95% confidence interval for a quartile change in HOMA-IR for obesity (BMI > 30) was 3.62 (3.30–3.97), and for the highest quintile for the triglyceride/HDL the ratio was 2.00 (1.77–2.26), for GGT it was 1.40 (1.24–1.58), and for WBC it was 1.28 (1.16–1.40). The relationship of HOMA-IR to the various outcomes was broadly similar to that observed in prediabetics and diabetics with a few exceptions. Conclusions: HOMA-IR levels in a large sample of normal individuals are associated with poorer general health and adverse changes across a wide range of markers. A similar pattern of alterations is observed in prediabetic and diabetic samples. Impact: Clinically, checking insulin levels may be helpful to identify patients that merit further observation and are candidates for early interventions.

Development and Validation of an Insulin Resistance Predicting Model Using a Machine-Learning Approach in a Population-Based Cohort in Korea

“…Energy intake was significantly lower in the high-IR group than in the low-IR group only in women [ 28 ]. In NHANES (1999–2014), vitamin C and folate intakes are inversely associated with insulin resistance [ 29 ]. Therefore, lifestyles may not be strongly and directly associated with insulin resistance to be selected as the top features for the prediction model.…”

High-Risk Atherosclerosis and Metabolic Phenotype: The Roles of Ectopic Adiposity, Atherogenic Dyslipidemia, and Inflammation

“…45 In this regard, it should, however, be noted that insulin resistance and compensatory hyperinsulinemia have been linked to the pathogenesis of CHD and cardiometabolic endpoints even in the absence of diabetes mellitus. 51,52 Lifestyle link. Numerous lifestyle factors, dietary and nondietary, negatively affect insulin sensitivity.…”

Associations between urinary hydration markers and metabolic dysfunction: a cross-sectional analysis of NHANES data, 2008–2010

“…BMI categories were defined as underweight (BMI < 18.5), nor mal weight (18.5 ≤ BMI < 25), over weight (25 ≤ BMI < 30) and obese (BMI ≤ 30) [21]. Elevated waist circumference was defined as > 102 cm (male) and > 88 cm (female) [22]; elevated fasting plasma glucose (FPG) ≥ 100 mg/dL (prediabetes) [23] or antidiabetic medication; elevated HbA1c ≥ 6.5% (diabetes) [23]; elevated insulin ≥ 15 µU/L [24] or antidiabetic medication; elevated HOMA-IR ≥ 4.0 [25] or antidiabetic medication; elevated triglycerides ≥ 150 mg/dL [26] or antihyperlipidemic medication; reduced HDL < 40 mg/dL (male) and < 50 mg/dL (female) [27] or antihyperlipidemic medication. Hypertension or elevated blood pressure was defined as systolic ≥ 130 mmHg or diastolic ≥ 80 mmHg [28] or hypertension medication.…”